The goal of my work is to study the biologic and prognostic significance of oncogenes in breast and colon cancers. First, I am determining the biologic significance of c-myc overexpression in colon carcinoma cell lines. Second, I am examining if underexpression or abnormal expression of a putative repressor oncogene, E-cadherin is a negative prognostic factor in human breast tumors. Third, using an expression cloning approach, I am attempting to clone functionally significant oncogenes in breast cancer. cDNA's from breast cancer cell lines with amplification at the 11q13 loci will be used to transform a nontumorigenic cell line, MCF-10A. The 11q13 amplification is intriguing because it is frequently amplified in human breast cancers and associated with a negative prognosis.